1. Technical Field
This application relates to computer storage devices, and more particularly to the field of allocating storage devices for use.
2. Description of Related Art
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units (host adapters), disk drives, and disk interface units (disk adapters). Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. No. 5,206,939 to Yanai et al., U.S. Pat. No. 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
In some cases, it may be possible to organize storage into “pool” that are accessed by an application or set of applications (e.g., owned by a particular user or organization). Such pools are useful for a number of reasons, including the ability to manage and control storage for a particular user/organization. A storage pool may be assigned by a storage manager, who handles management of storage for an entire storage device.
A drawback to using storage pools is the necessity of manually monitoring the size of the pools to ensure that none of the pools run out of space (i.e., an amount of data is written to a pool that exceeds the pool's capacity). In large systems, this may be impractical, especially if there are a significant number of storage pools.
Accordingly, it is desirable to be able to allocate more space for storage pools in an efficient manner.